Piezoelectric sensors
CA 2109132 A1 · Owner: Halvorsen, Donald L. · Inventors: Thompson, Mitchell; Chatigny, John V.; Radice, Peter F.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A traffic sensor includes piezoelectric sensors having different polarities in different lanes of the roadway so that traffic data for different lanes of a roadway can be detected from the polarity of the received signal(s). The piezoelectric sensors may be formed by splicing oppositely polarized piezoelectric cables or films, by changing the applied electric field during manufacture so that adjacent portions of a piezoelectric cable or film have different polarities or by applying an electric field of a reversed polarity to respective longitudinal sections of a piezoelectric film. Traffic data from up to eight different lanes of traffic can be detected using only two piezoelectric sensors …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 25, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 25, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 25, 2015.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.